Exemplary embodiments pertain to the art of electric machines and, more particularly, to a method of blocking electro-magnetic interference (EMI) in an electric machine.
Electric machines, particularly high voltage electric machines, produce electro-magnetic or radio frequency interference (EMI) at high levels. The EMI can interfere with other electronic devices. Therefore, it is necessary to prevent stray EMI from escaping from electric machines. Moreover, federal regulations establish limits on EMI/RFI levels for electrical products. Manufactures must ensure that stray EMI emissions remain below the federally mandated levels.
High voltage electric machines typically include a housing formed from an electrically conductive material. The housing includes an interior portion and an enclosure that provide access to power connections, switches and the like. The enclosure includes an access port that is provided with a cover. The cover is also formed from an electrically conductive material. In order to confine EMI emissions to the interior portion, the housing and cover are connected to an electrical ground. Various applications require that the enclosure remain sealed. In such cases, in order to ensure that all portions of the housing remain electrically grounded, a gasket formed from an electrically conductive material is positioned between the enclosure and the cover.